SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3d43d4536df302c8cb9cbd34df48153e22f759b3309d9f252002f87c23a4011' 
  AND token = 'kdSg2+RJTqFzieHQ3IrVea2jqUAkkCojHOGcc0VcZGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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