SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '923135977be5bb2fe45daf9c288a1ff0846a091ef3ff27236604f3506a9b6141' 
  AND token = 'kZPRsEHO82Pq3UVROw1bBWg4mFRZkKMOyXMSEIVvVCo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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