SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '871e023d68c119de5f4946f8b844ae71a6291233d67126cea4489f3a2a9790f3' 
  AND token = 'hYsRLqiNBo3VoRrMMfx7IqU0pzTPKnuN2aEYgvMHnUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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