SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a30006751de3e2d0488d52cb6a6fb4ef437ace236bb6ca7a7f344044d957f24d' 
  AND token = 'wGsdnIDsmCGDfZ5pTSSpsP6nqqKk7uxlDxhTMImoOBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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