SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83fa83663dcd4454b7f35574a41574956b09e3a49759c30ae8b1b9bb3757f617' 
  AND token = 'zlTdVG0KvMrHpYgd4HH9E7F+TAMdavYxyIOEqbNXTBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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