SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd4683ab6e030d44f38263ce4e72decab3919847c11a17d63c74ddf62b5b7813' 
  AND token = 'sDpyuU5RzOC4t5TiYNeAlNO/rYmAKQxff1m8Kqk4Ay0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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