SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb4bf55e4fe9f40bb06477c722df33baa9d3050009570e3ad3e2e586ca9f3375' 
  AND token = '+XkqEHG/v/gQ4IBzPQ/9FPjUegvHgSzv5nuGZ8o/tFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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