SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d34472040ae1106046730178194854b29671b89a9d7eeb1b32e2da12675d23f' 
  AND token = '2kVF4N2VyHPXOT4GRGocI0yCQKHXsC4/zkCRXtedTQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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