SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f6477994f4a916678145d43bb5c8056a33dd1e79f39fbe4532d284570f30f0d' 
  AND token = '2Owv2l5SmWnDJOoMrgTrCnquQoXQDgfpZY/LqEmXwe4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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