SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da9a65d78530e90cf66cf0dbbaac83fee97599d62610b00ec099231bfe5e43ce' 
  AND token = 'FqJoU/Va/upLsSxUQspusjokKkWWddeR5OTchEYqvhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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