SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '496f817a036fb0fbc90a8ce0339bc7cd27185a46e502df111365185778d283bf' 
  AND token = 'JgEDMTcVC1+B8tH5z0YrNESiNbNOYJApdjvK+RHWkJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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