SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3d11dcd352a98b97212c383d14e22be99bf9763b825e4029d97743e28cd8a3b0' 
  AND token = 'FPHWhh9gOc3JmtG73sUUUs+rQMMWG6JXkACgQFxVgZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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