SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '846f034c9f198a06ee21534c86363301772a6bb24e7a670dfd9f6858eac57b17' 
  AND token = 'I4oFFIi14BheaEQS91AF9noLOHeUHpvqf+AtGIKB2YQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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