SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '793e553c457c0d01250cbbb0e9d3d0a0229bb1546ab065bd47942be76abe7556' 
  AND token = 'wUZWWAQ9DJFluz8fvZbfehl67+iakakFjj+aynmiW10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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