SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc582fd388db0e36caec650b142232d69556cb4b6873ec8995b48ed452541159' 
  AND token = 'mZY2SpJMZJLBSjn3Zc1xG+tjI0bLs8gVn0KsAEULNUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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