SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5b3f2ddd26d76f350b5a289977558e69bdd099ed1b0bb051e4704eec73c2b16b' 
  AND token = 'TmvfsNM39Il25yjwFVvnCnBp0Wa6rFVjZCsJ0G+DTKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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