SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '535ef254153cbbfe6bcfd5e90d8d1f9074469603f94d34f2ffc32c867091c306' 
  AND token = '0M+pCGDOWaEpl5dvVsTW5TgZWKQVgQ9zHj+VnpM1lKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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