SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6772754980ff883290c7e1af263385a44e60be5c7537bd8527fbe17119cfd54f' 
  AND token = 'R2HnuXmikHepY7DoBXiV1ABHgxtKyvlXlpA2AMhwLTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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