SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d8d82d34f4838e17010b807e8351c37d06ac108ef4748c78aaafc5f34eef080' 
  AND token = 'EHGj1eipaAIqwKXNDPtgXt8zIUCHor8cXNhmYYj80JE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}