SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0521cc02c8a63888b6b63b93db6652e7efb48e7b33aa05127d0d95ca40f0405' 
  AND token = 'QYqJ4m49YICV4flHgExneeSPNFf8nBZHX3SL3Z/iprw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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