SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79159a7f65b10c7b13afd8ae0d731980caa9548467a3843d60caed4ca49aecca' 
  AND token = 'Aw21vCjUrNSW/KJcb0qpAv1aSKYa7i1/h/Y9+iTw+js=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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