SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91baf308869f634a9701def59c01b0612b649ff6db808047e0080005515c3408' 
  AND token = 'pzyxmU0mP5B//3jlph1j+U2R4YQVkYCKXPKZLwYIhhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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