SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbc3dd73d722d80217ef7b94f28fe957f900790692d929853b7fc21a793efda9' 
  AND token = 'AFJlyq9SHbZi8781wd7bFdGH0noLhsp2v/fHova3oCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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