SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92df2c9e78fd98d01a32a17e081616bf91b235df63f88e6a937108bce166a371' 
  AND token = 'aCuJPT8A0bUrIIETYQBRQ2G7xL2I4i5mUkG0t00aabg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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