SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7488624a9750b6623d0159f3eb8489124374e3703eb86b67b4a00fc854a12f2' 
  AND token = 'tM/hPoEMEHF1OTEjaE3or7rgUGVibJ8vjzVYoADvLJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}