SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '61b90602222b35a1a3748a743f6242fe6691e914eeb3e85984a2b4c43f5a3159' 
  AND token = 'D/RhGCOotSlhBOQhfKlwzFDJha6VVZR23+xqwt78lWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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