SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b85af09af2a02c318b5c8e3cc938155e5bbc746eb028fc49e3d5288fb081d30' 
  AND token = 'D7y/g+2pbnrExXBrDBHvRhnU2qzttoB6tHO/ZXrg9JI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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