SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '534ff4514d0b5ff289803841e0250f0e6626220057f54ac6fad962696d0df15a' 
  AND token = 'G6vqQVWjcccNU3YQnjP6UiOjSzASQ/SIbXmmmyeiAJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}