SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6337d880012cb6f3e3c64cd4bfbc4229d13e858b4e9806db564f5e6bd7c50672' 
  AND token = 'vQugEcxpUD01nQ+q9lFLtGHyHpYJh1fKDXBk7eJ2dUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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