SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e73a1927a0ca87cc9b5b2564c5da0dd51466e2744c456938c7972f359404d83f' 
  AND token = 'it/LIzmichfxNmoNDPzTHZBCW9+5x8hpiV1R0OCVSa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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