SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4dca805f0a1e19f3a47785de8f7099f686da5b65ea267d1889929715ec98356' 
  AND token = 'w4vdA2Wg99hO+5XLAEXVf9Hr18xJAiUMgwCgflNA1rc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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