SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fce02e0e891d3f7d1c14330896d12be3ccbda34075c5da457b8521ce21668319' 
  AND token = 'zF6vAuNpg33N04nc2efMzvqmjMxICBaZqwKoh5ykJcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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