SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e8f3d4da19214a846cbd5b96a05d191b61159fca5ae0d29c630809c735405a8' 
  AND token = 'dCehfyqkM3vm6tu0pqw+/RQ3mf99V0Ix/XCgxQs6HWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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