SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7b68837029e339c637f9b51d3fa1e9faf06785a009d8d3c005bf1944f977af8c' 
  AND token = 'go7b91l5nLOM766umdsUUg8bmolyXpPhX1rNSFPucGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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