SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2371578e3873e0c7c836004c951fd99e99d582727dff115b7c21be2f3a8fbb8' 
  AND token = 'ebdguOWKgrgIKTsmTRSBcpVS+9dZ2HnvsmwGiUw1a6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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