SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d0306c9a92d8464cf7df75341adedd2653af40d174433a64fab5ae28615355f' 
  AND token = 'mlYPNQuXjgnrpCZvaDLVB5PGdLyhXxmCvRd52i6+Ooo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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