SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b9e36ca79343c1b544630b85b3f94b3cbbdd3f9e745ed72d3a618fbe910564a' 
  AND token = 'UY+lOtFHjulnjB/uYDPOHpQ7Kgzhr3VBwDZjTT3Qwxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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