SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e7ac971c0ece867955432a097dfa3063eb647b305295e0e693512f268726f6e0' 
  AND token = 'yrNgryHKbXllybPBiIrUTfEYwKUNkTMmJlFh+Hw61rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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