SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f8646aae395aa9da03f80028d94ce62c52f635c597234b87219d51401ee78e46' 
  AND token = 'nHqFSqjjCIeUY1OselbS0tYZoFdhIXeJMyJFcwhlXpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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