SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b44b4f4fd91cd7480f10a5f6a441ea49699004aeed9929af7a515b830951703a' 
  AND token = 'zl19YS48bxvu0kBmjgBTNoJslRn5Bcy+anvZ+bQN8AY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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