SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '40a74dd50e42022ffa753188d96e53ee312297f1ef1c504f7575d367c1c96a2b' 
  AND token = 'JDFbwKGrXki5KKBsfcu5wzQ6U6JFsbj1+5usXT7m24s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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