SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de95d3a60cc42cf86e750636f98a8986bb8a137057bdb622e420bcba102c701a' 
  AND token = 'Kf1D3eYUdJZbDv77hrluip0KzkFOAvYJx95igwRkCBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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