SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd903007b3ec3bb913260348d1657559e50d9e6e41bb3ff868d7e2b8487c1fccb' 
  AND token = 'tboPfXcaXtBr9O7jsK/qbtlJsL8wr3oQ7UKQs7MMHOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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