SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c63ea252ba44a61654c73e9b1f2b3f99690b85ebcfd81833578a68f16cf9a570' 
  AND token = 'R+kBIPD4JQFWQ/secuSpiO2K2qPRGH1aND9fc+i+BKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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