SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3b28a7eb9c5dc9ce44c312dbab8d2af07d8240ca475fd34c57d315ab2c770d0' 
  AND token = 'Rbaf0DE7tfRF3Bryp2v3R4kkYsTpN7y0kei7k5fLJcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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