SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75e018d6bf8c759fba26676d1870fd5186be3ad7c355cc8b22ab50449017cb04' 
  AND token = 'tK9ZMXhFLuwwhsJWgZI2M2eLvgTyTZFIhDMicmjm4xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}