SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd94c79451e00a61a2d8a2a62cb76755ac9401139e2401e3bac9b5e6fafb1be79' 
  AND token = 'mqVWBJJaWgSmkkvIgfCWGyiTO+jjrcH31neFFXvNKSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00076

JSON explain

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