SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc568db837a8de0dd91f143259848abfefccb67abb78d1dc92383fd4939b305b' 
  AND token = '4qLBrm/7tJm1yQZ4wUquVha7PZ1yOO1umXRecGNog4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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