SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1e6b3c2e38e24a452ddcc1851e174595b49b5936d9189e4312ad2a154da9925' 
  AND token = 'qwo8TKjQExo6kEyEBsaEEW6MMJ0/xg8WjKa0xnyFSJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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