SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba796bd7a6d1ea633c1b58caf52c79e861a13414edc0150323c80585c43ac519' 
  AND token = 'M2XShDyo3WFq2b23KugE3NrupxLxeb4C++j6l7b7dao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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