SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e186daf255c4a449f9b6a80f36dec7404719a6577eed2c0471bf6cf3e2bb22e2' 
  AND token = 'jtgDDgyUhoSB6Q6aF5Slv6EhBrDBSfIxPowukz84sbg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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