SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab39d846cc7e338c43c8f62f5c7f541405b99f8b53da2fe2c625da67c2a21d73' 
  AND token = 'dKZOpCveZt9ra86Ne+6B3Q6AhAYoQ9PeIjwfraJpFMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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