SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5959eee007f6141aa6c54b47bd573c87c6ec11288f88efb1d3ee3c65eadcda7e' 
  AND token = '+SRkEEIrCGCVe5gXS3HOoqaWJUHAaaBfYz3zUhDiE4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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