SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6594765adbb208d37e7c64334ddee767c87a6e5d8a5b0ba97efebf32ffca995a' 
  AND token = 'K3rj96p3+C6zUv+UuMIyzHBf4AOr8Buu/A180FPvwYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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