SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b30bbd4574528cefbc406fa22ad5f84af1779813eb12ac913bed341ad4cfd78' 
  AND token = '+e9icZBQxF8Q1THWLCPlHUevdP8QKiCmOaVAOyB6HYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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