SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77d6a2eae4fdd3adb1daa3f4a901e0c4eacb9814355aca999d50f2a7ba830a28' 
  AND token = '+oPi/4B2ekTonGoxBbJW3MzzyHPK6HHIcHGqpvj29E4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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