SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'db283b0293deae9e478f7ab019dfa47992b745d6192e4cfc7d0c1b7bc184c52f' 
  AND token = 'PH/krYBuBBB/l77VSuH6lvgjZkZ0LTaYYcXFr9AfguI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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