SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb191998e45355ab651776c7c0eef23dee7c6f64d8a32bc8b240ef5a5ee11ae9' 
  AND token = 'MtokbwlSZdDg69X1KpbXj9pCyXDW4MyP4Kakk6eDMno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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