SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abc6816b455dbf31af5647dd073d3b9716aa82e061ec997aff963f9d43399517' 
  AND token = 'G4InseCigQxKlJ6BcRgqqTeJs49xJe7vr0iyNaHR6BI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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