SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66b999988c58c03bfda5c39724f5d739c28fc36754b7ac551b20876e824e83da' 
  AND token = 'QVbU3H0ZU4hFErcxJwDB24YcXYKH1/+YFfvDqitNIZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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