SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a1b5633cb3e611b0ead91d1cd3ed80b9235f9cf4df948207a1d8fa265a71cae5' 
  AND token = 'ZCTHFjmoCpI2fj1vRB3smgOdWPBdgu9nwYr4zk/3+rg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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