SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba85d20387197e565672c3b88a805b764ab6167cfcb91d646438863ca05969a6' 
  AND token = 'f/o58tAZP193gK8QpY6J0jiKWHPy6+36drbwroktCeg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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