SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7a9466cf1e63450d0375f48b8c0bdcda0466e1982f15e3c957d80d01d043531' 
  AND token = 'foLyLKiBbsAffSQ7mGQYNNOEgXJFFrIrhUMQHo4gVms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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