SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '261d2205a5286db4854d6a3d93350bc0aa5f37b590c7f8dd81be393f8dcee8a6' 
  AND token = 'g0vlD2EyVNKDGQS5dADHZr1Ud1ltMflnrRySDnzafgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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