SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cd3f90f402beb3bf8e58635e9e985b64835e58d91c43022ad943768995cdeaa9' 
  AND token = 'hkh46zrR72/lhVWcakAU5sxOFPERRPcJhObxCQsHn0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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