SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae387eba25c23a7073b8fd77f31d53e270ba13a66db49e47a7f1acdaeaf7921e' 
  AND token = 'yUe/UUAM3WoI3rshck0dM1GVjV4kJU5odDnDqDTiyTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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