SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dca02c7e8600a2a1726e74c526a61d0dd1d92879b48359d8793611fe7e0e6cd' 
  AND token = 'qn6/cuFFPI4CJkWC3nWqBXTxfKXY6EGNWUdlptvfO8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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