SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58c8d7a671f8f6a31167da7568c23a5179d19e28e6e95f3172ba84fe2fbbf760' 
  AND token = '2XyAGOvaULI4LtcgTI9WmvGbAcqFwVCNMflOxKoTo5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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