SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ce925c3020fbcefbc5df16f3bb812196852c62febf8f918ed0cc8e1488c97806' 
  AND token = 'h53c0VpShI/9opj25GxN6cXPqCTxG1qPAQQCTrcnK4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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